Molecular Analysis of Ephrin A4 and Ephrin B1 in a Rabbit Model of Craniosynostosis: Likely Exclusion as the Loci of Origin

The clinical manifestations, molecular mechanisms and treatment of craniosynostosis

Craniosynostosis is a major congenital craniofacial disorder characterized by the premature fusion of cranial suture(s). Patients with severe craniosynostosis often have impairments in hearing, vision, intracranial pressure and/or neurocognitive functions. Craniosynostosis can result from mutations, chromosomal abnormalities or adverse environmental effects, and can occur in isolation or in association with numerous syndromes. To date, surgical correction remains the primary treatment for craniosynostosis, but it is associated with complications and with the potential for re-synostosis. There is, therefore, a strong unmet need for new therapies. Here, we provide a comprehensive review of our current understanding of craniosynostosis, including typical craniosynostosis types, their clinical manifestations, cranial suture development, and genetic and environmental causes. Based on studies from animal models, we present a framework for understanding the pathogenesis of craniosynostosis, with an emphasis on the loss of postnatal suture mesenchymal stem cells as an emerging disease-driving mechanism. We evaluate emerging treatment options and highlight the potential of mesenchymal stem cell-based suture regeneration as a therapeutic approach for craniosynostosis.

Molecular Analyses in a Rabbit Model of Craniosynostosis: Likely Exclusion of Known Candidate Genes as the Loci of Origin

OBJECTIVE

Craniosynostosis (CS) involves the premature fusion of one or more cranial sutures. We work with a naturally occurring rabbit model of CS with an undefined etiology. Known causes of coronal CS were evaluated to identify potential associations with CS in the rabbit.

DESIGN

Candidate genes were sequenced in control New Zealand White (NZW) rabbits (n = 4) and synostotic NZW rabbits (n = 4). Variants were identified by alignment using Clustal Omega.

OUTCOME MEASURES

Single nucleotide variants (SNVs) were classified according to phenotypic associations and predicted impact on protein structure. Human correlates were identified in the database of single nucleotide polymorphisms (dbSNP).

RESULTS

A total of 21 SNVs were identified in the 10 genes examined. Variant classification and inheritance patterns are inconsistent with causality.

CONCLUSIONS

The genetic basis for disease in the CS rabbit likely involves novel loci and is not associated with known causes of coronal synostosis.